We demonstrate that both in-plane molecular rotational and tilting angles of the molecular orientation can be determined using the σ* resonance of sulfur (S) K-edge near-edge X-ray absorption fine structure. We examined dinaphtho­[2,3-b:2′,3′-f]­thieno­[3,2-b]­thiophene (DNTT) thin films on silicon dioxide (SiO2) and copper oxide (CuO x ) substrates which are relevant to the cost-effective organic field-effect transistors. In-plane directed transition moments were attributed to the electron excitation from S 1s to the largely overlapped σ* orbital related to the C–S bonding at the thiophene site. Under coexistence with a minor component of the amorphous region, it turned out that the DNTT domain with the single-crystal structure has the c-axis normal to the substrates; the DNTT molecules on SiO2 orient at a tilting angle (β) of 85° and an in-plane rotational angle (ΦM) of 77 and 103°. In the case of the film on CuO x , values of 84° for β and 73 and 107° for ΦM are acquired. The amount of the amorphous region in the film on CuO x was larger than that on SiO2. Our approach is applicable to other sulfur-containing molecules with a small population of the lowest unoccupied molecular orbital on the S atoms.